Surgical Instrument Comprising Electrode Support

ABSTRACT

A branch of an instrument comprising a metal part, which is embodied in one piece seamlessly, which comprises the electrode support as well as the electrode plate and connection webs. Preferably, this metal part is produced in an additive production method, for example selective laser melting (SLM). The branches are suitable for instruments for open surgery as well as for laparoscopic and flexible endoscopic instruments.

TECHNICAL FIELD

Embodiments of the invention relate to a surgical instrument for theelectrosurgical monopolar or bipolar application of current tobiological tissue, in particular a sealing instrument.

BACKGROUND

Instruments for the coagulation of biological tissue between twobranches of a tool comprising at least one movable branch are known fromthe state of the art. For this purpose, EP 2 554 132 shows aninstrument, the branches of which in each case comprise an electrodesupport and a thin plate-shaped electrode. The electrode support canconsist of a massive metal part or of a plastic-coated metal part. Theelectrode is connected to the electrode support via a plurality ofpoint-like welded connections. On the one hand, a reliable mechanicalconnection and, on the other hand, only a small heat transfer betweenthe electrode and the electrode support is to be attained with this.Even though the seams have only a small diameter, they also have only asmall length (expansion in heat flow direction), which limits theireffect as heat barrier.

On the one hand, a mechanically stable and electrically reliableconnection must be created between the electrode plate and the electrodesupport. On the other hand, the heat transfer is to be minimized.

SUMMARY

Based on this, it is the goal of embodiments of the invention to specifyan improved surgical instrument, in particular comprising an improvedbranch for the use in open surgery, for laparoscopic and endoscopic use.

This object is solved by means of the surgical instrument, in particularwith an electrosurgical instrument according to embodiments describedherein.

The instrument according to embodiments of the invention comprises abranch, in the case of which the electrode support and the electrodeplate are connected to one another seamlessly in one piece via aplurality of webs. The webs and also the transitions between the websand the electrode support on the one hand, and the electrode plate onthe other hand, are thus embodied of material with the same compositionand structure without any transition. The preferred material therebycomprises sufficient electrically conductive characteristics, so thatcurrent can be applied to tissue by means of the electrode plate. Seams,as they are created by remelting parts of an electrode plate or of abranch support when made of a plurality of individual parts, arecompletely missing here. This concept provides for the minimizing of thedimensions of the webs to what is necessary electrically, mechanicallyand with regard to production. It furthermore provides for a minimizingof the length of the webs. Preferably, the length of a web is at leastas large as the square root of its average cross sectional surface. Morepreferably, the length of a web is at least as large as the square rootof its smallest cross sectional surface. Due to these measures, the heattransfer resistance from the electrode plate to the electrode supportcan be maximized. This is in particular the case, when a plastic, whichis injected into the slit between the electrode support and theelectrode plate, supports the mechanical connecting effect of the websor also takes it over to a large extent.

The embodiment of a heat resistance, which is as large as possible,between the electrode plate and the electrode support can be used tokeep the side of the branch, which faces away from the electrode plate,as cool as possible during operation. While the tissue seized betweenelectrodes and thus also the electrode plate, which is in contacttherewith, can heat up to temperatures of above 100° C., the electrodesupport and thus the outer side of the branch on the rear side can bekept at a lower temperature, which prevents or at least reduces damagesto the tissue, as compared to the electrode plate. Tissue damages canalready occur starting at 40° C., but at least starting at 60° C., forexample. This provides for a very precise and specific tissue treatmenteven in the case of difficult surgeries and in the direct vicinity tosensitive tissue, such as nerve tissue, for example.

In the case of a specific embodiment, the webs are arranged so as to bespaced apart from the opening of the slit. Through this, the small heatflow from the electrode plate to the electrode support is kept away fromthe edge of the electrode support, so that the edge temperature of thebranch can be lowered further.

The distance of the webs from the edge contour of the electrode supportcan furthermore be larger than the width of the slit. This promotes theabove-mentioned effect.

The webs can comprise a round cross section. However, it is alsopossible that they comprise a differing non-round cross section, whereinthe cross sections of all of the webs can be embodied equally or also ina different manner. The cross sections of the webs can furthermorecomprise the same or different orientations, so as to maximize the crossstability of the support of the electrode plate at the electrodesupport, for example.

The webs can comprise a largest diameter, which is smaller than the slitwidth. The webs are then very delicate and have a small heatconductivity. If the electrode support comprises a bowl-shaped crosssection, the length of the individual webs can be maximized, whichfurther increases the heat resistance.

The electrode plate can furthermore transition in one piece, seamlesslyinto the electrode support at one end. The electrode plate can be aflat, possibly profiled part. The design of the electrode surface, whichfaces the tissue, can be designed freely, depending on the application.In particular, the electrode plate can comprise a circumferential edge,which reduces the slit width at the opening of the slit.

Preferably, the electrode support, the webs and the electrode plate areproduced in an additive or generative production method, respectively.Preferably, they thereby consist of a homogenous material. In particularthe selective laser melting (SLM) is suitable as additive productionmethod, in the case of which the electrode plate, the webs as well asthe electrode support are made of metal powder by means of lasersintering or laser melting, respectively. The electrode plate, the websand the electrode support thus have a homogenous fine structure. Due tothe material and the method, the material stabilities, which can beattained, are high and can be compared to casting methods. In the caseof structures comprising only a few undercuts, the metal injectionmolding method, MIM method, can also be considered as further productionmethod. An increased surface roughness of the webs, of the electrodesupport and at least of the side of the electrode plate, which faces theelectrode support, provides for a solid adhesion of plastic to thesesurfaces. In particular if the slit formed between the electrode plateand the electrode support is injected with plastic and, if applicable,if the electrode support is also otherwise insert molded or coated withplastic, respectively, an firm metal-plastic connection is attained.This is advantageous in particular with regard to the hygienic demandson surgical instruments as well as with regard to possible cleaning andsterilization cycles, in the case of which the instrument, in particularthe branch, is subjected to high thermal and also chemical stresses.

The insert molding of the electrode support with plastic effects atleast an electric and, depending on the plastic thickness, also anoticeable thermal insulation, which is advantageous.

The plastic insert molding can further be used for providing amechanical calibration of the electrode support, for example in the areaof its bearing bore. For this purpose, the electrode support comprises across passage, the accuracy of which is of secondary importance inresponse to the production. The accurate bearing bore can then beattained in response to the insert molding of the electrode support withplastic in the plastic injection mold by using a mold core, whichextends through the cross opening of the electrode support and whichaccurately determines the position of the bearing bore in the plastic.Every time the above and below description as well as the claims referto plastic or plastic material, respectively, this also comprisesmaterials comprising insulating characteristics, which cannot beassigned to the group of the plastic materials.

Further details of advantageous embodiments of the invention are thesubject matter of claims, the description and/or the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the instrument according to an embodiment of the inventionin perspective overview illustration,

FIG. 2 shows the tool of the instrument according to FIG. 1 inperspective overview illustration,

FIG. 3 shows a branch of the tool according to FIG. 2 in side view,

FIG. 4 shows the branch according to FIG. 3 in top view,

FIGS. 5 and 6 show cross sections of different embodiments of branchesaccording to FIGS. 3 and 4,

FIGS. 7 and 8 show cross sections of webs in different embodiments,

FIG. 9 shows a cross section of a hollow web,

FIG. 10 shows a longitudinal section through a hollow web comprising aspacer element accommodated therein,

FIG. 11 shows a horizontal section through a branch according to FIG. 3or 4 comprising a plastic coating in the area of the bearing bore,

FIG. 12 shows a cross section of a modified embodiment of a branchaccording to an embodiment of the invention.

DETAILED DESCRIPTION

By way of example, the instrument 10 illustrated in FIG. 1 isillustrated as tube shaft instrument for use in open and/or laparoscopicsurgery. It comprises a shaft 11, at the distal end of which a tool 12is arranged. A housing 13, which comprises a handle 14 and which isconnected to the proximal end of the shaft 11, serves to handle theinstrument 10. The instrument 10, however, can also be embodied asflexible endoscopic instrument, wherein the tool 12 as well as the shaft11 are then correspondingly small and delicate and the shaft 11 isflexible. The basic description below also applies for such embodiments.

FIG. 2 illustrates the tool 12 with two branches 15, 16, which cooperatein the manner of pliers and which, on principle, comprise the same basicdesign. The following description of the branch 16 illustrated in FIGS.3 to 6 thus applies accordingly for the branch 15.

The branch 16 is illustrated in FIG. 4 by omitting its plastic jacket17, which, in turn, is illustrated in more details in FIG. 5.

FIGS. 3 and 4 thus only illustrate the part of the branch 16, whichconsists of metal. This metal part 18 is divided into an electrode plate19, which is embodied in the manner of a thin, possibly formed sheetmetal plate, an electrode support 20 and a plurality of connecting webs21, which are arranged therebetween. The electrode plate 19, theelectrode support 20 and the webs 21 are embodied seamlessly from ahomogenous material in one piece. As is illustrated, the electrode plate19 can be embodied so as to be flat and, according to FIG. 4, so as tobe stretched in a straight manner. However, it can also be embodied soas to be curved in one or a plurality of directions, if this is desiredfor a certain use. For example, the electrode 19, in top view, can beembodied so as to differ from FIG. 4, following a curve. In addition, itcan be embodied so as to be bowl-shaped in a convex or concave mannerand, if desired, it can be embodied so as to be profiled in each of thementioned cases. The profile can consist of teeth, cross webs,longitudinal ribs along the edge contour 22 or the like. It is furtherpossible to provide the electrode plate 19 with a continuous slit orwith a slit, which ends shortly upstream of the distal end, foraccommodating a blade. In any event, the electrode plate 19 comprises anedge contour 22, which extends along a side, then across the distal endand then along the opposite side (see also FIG. 5), which is preferablyembodied so as to run parallel to an edge contour 23 of the electrodesupport 20.

As is shown in FIG. 5, the electrode support 20 can be embodied as fullprofile and, according to FIG. 3, can extend at a constant or also at achanging distance to the electrode plate 19. Between one another, theelectrode plate 19 and the electrode support 20 define a slit 24, theopening 25 of which is defined all around along the edge contours 22 and23 between the latter. As can be seen, the opening 25 can comprise ahomogenous width W all around, measured between the edge contours 22 and23. According to FIG. 5, the edge contour 23, based on the edge contour22, can additionally be offset towards the inside. The electrode plate19 projects beyond the electrode support 20 here. The ratios, however,can also be reversed. The electrode plate 19 can comprise a thickness D,which is smaller than the width W of the opening 25 of the slit 24 (FIG.5).

As shown in FIG. 5, the webs 21 are preferably spaced apart from theopening 25 and thus from the edge contours 22, 23. The webs 21 mergeseamlessly into the electrode plate 19. The webs 21 also mergeseamlessly into the electrode support 20. The length of the webs 21 ispreferably at least as large as the width of the opening 25.

As shown in FIG. 12, the edge contour 22 of the electrode plate 19 cancomprise an extension in the form of a projection 35. This projection 35is arranged at an angle, preferably at a 90° angle, to the plane of theelectrode plate 19 and can partially or completely project beyond theopening 25 of the slit 24. The projection 35 can comprise a height H,which is larger than the thickness D of the electrode plate. The heightH of the projection 35 can lie within the range of between 0.3 mm and0.5 mm, preferably 0.4 mm. The thickness of the projection 35 ispreferably equal to the thickness D of the electrode plate 19, but canalso be slightly larger or smaller. The projection 35 projects beyondthe plastic jacket 17, so that the outer flange 37 of the plastic jacket17 is arranged at a distance to the outer flange 38 of the projection35. The outer flange 37 of the plastic jacket 17 is arranged closer tothe center of the electrode support 20 as compared to the outer flange38 of the projection 35. The distance between the outer flange 37 of theplastic jacket 17 and the outer flange 38 of the projection 35 ispreferably slightly smaller than the thickness D of the projection 35.The transition area 36 from projection 35 to the electrode plate 19 ispreferably embodied so as to be rounded so as to protect the tissue. Asillustrated in FIG. 12 at a location (on the right-hand side of thefigure), the geometry of the edge contour 22 with the projection 35 of abranch 16 extends preferably along a side, then across the distal endand then along the opposite side of the electrode plate 19. This edgecontour 22 can comprise the same geometry continuously throughout, itcan also comprise breaks in the form of recesses. As described, an edgecontour 22 with projection 35 supports the reliable closing of vessels.

The metal body described insofar, which consists of electrode plate 19,electrode support 20 and webs 21, is preferably produced in an additiveproduction method, for example powder-metallurgically by means of lasersintering or laser melting (SLM method). The webs 21 thus have the samematerial structure as the electrode plate 19 and the electrode support20 as well as the same stability. The diameters of the webs 21 can besmaller than the length of the webs 21. The cross sections thereof canbe embodied so as to be round or substantially circular, respectively,for example, as illustrated in FIG. 7, or can be embodied so as to benon-round in accordance with FIG. 8. High mechanical stability can bepaired with a low heat conductivity can be paired in this manner.

Preferably, the slit 24 is filled with a plastic, which merges into theplastic jacket 17 on the outside. The slit 24 is thus closed, so thatthe permeation of liquid, bacteria or other biological materials iscounteracted. The plastic furthermore adheres to the surfaces, whichface one another and which define the slit 24. In addition, the plasticjacket 17 can adhere well to the rear side of the electrode support 20,the lower side in FIG. 5. The plastic jacket 17 effects an electricaland thermal insulation of the electrode support 20 against surroundingtissue. The plastic in the slits 24 effects a mechanical support of theelectrode plate 19, as well as a thermal shielding thereof against theelectrode support 20.

FIG. 6 illustrates a modification of the cross section of the branch 16,in particular with regard to the embodiment of the webs 21 and of theelectrode support 20. As illustrated, the latter can be embodiedapproximately in a bowl-shaped manner, whereby the length of the webs 21and the inner width of the slit 24 become larger. The webs 21 can beembodied in a cylindrical manner or also so as to thicken at one or bothends. Otherwise, the above description applies accordingly based on thesame reference numerals.

Instead of delicate webs 21, hollow webs 26 according to FIGS. 9 and 10can also be used at one or a plurality of locations. These hollow webs26 can enclose a channel 27, which breaches the upper side of theelectrode plate 19, for example, and which is suitable to accommodate aspacer 28, for example made of plastic, ceramic or the like. Accordingto FIG. 10, the hollow webs 26 can form a connection between theelectrode plate 19 and the electrode support 20. However, they can alsobe embodied as blind pin, that is, they can end at a distance upstreamof the electrode support 20. In this case, they do not contribute to theelectrical and mechanical connection between the electrode plate 19 andthe electrode support 20. The connection is then taken over completelyor partially by other webs 21 and/or by the plastic arranged in the slit24.

The plastic jacket 17 can extend beyond the electrode support 20 to ajoint section 29 (FIG. 3) and, if applicable, further to an operatingconnection 30. The joint section 29 serves to embody a pivot joint so asto be able to open and close the branches 15, 16 in the manner ofpliers. For this purpose, the joint section 29 is provided with athrough opening 31, which extends across the joint section 29 and whichcan be embodied so as to be round or non-round and which preferablycomprises a diameter, which is larger than the outer diameter of a bolt32, which is provided for support (FIG. 11). The plastic jacket 17preferably extends through the through opening 31 and forms a bearingsleeve 33 at that location. This bearing sleeve 33 is an integralcomponent of the plastic jacket 17. It insulates the metal part 18against the bolt 32 and at the same time centers the latter in thethrough opening 31, namely largely independent from productiontolerances of the metal part 18.

The instrument 10, which has been described insofar, operates asdescribed below.

The electrode plates 19 of the two branches 15, 16 are connected to anelectrical power source, for example an HF generator, via lines, whichlead through the shaft 11, and via a connecting cable 34. In response toactivation, a voltage is present, so that power is applied to the tissueseized between the branches 15, 16. For this purpose, a hand lever isoperated on the handle 14, so as to close the branches 15, 16 and so asto seize tissue between them. By supplying power, the temperature in thetissue rises, whereby it coagulates. The temperature of the electrodeplates 19 thus partially also rises beyond boiling temperature. Theheat, however, is largely limited to the electrode plate 19. The plasticarranged in the slit 24 comprises a heat conductivity, which is smallerthan the heat conductivity of the electrode plate 19. Due to their smallcross sectional surface, the webs 21 additionally transfer only littleheat energy, so that the electrode support 20 remains cool for the mostpart. The preferred large heat capacity of the electrode support 20accommodates the small transferred heat quantities with only a smalltemperature increase. This effect can be intensified in thatheat-buffering materials, in particular latent heat stores, for examplewax, are arranged in one or a plurality of hollow chambers of theplastic and/or of the electrode support 20, wherein the storagetemperature is preferably defined to a low temperature range, which doesnot damage the issue, of 60° C., for example, or less. The outer sidesof the branches 15, 16 can thus be kept sufficiently cool even inresponse to a longer use.

A branch 16 of an instrument 10 comprises a metal part 18, which isembodied in one piece seamlessly, which comprises the electrode support20 as well as the electrode plate 19 and connection webs 21, which arepresent. Preferably, this metal part 18 is produced in an additiveproduction method, for example selective laser melting (SLM). Byeliminating welds or seams between the electrode plate 19 and theelectrode support 20, connections, which conduct heat poorly and which,simultaneously, are mechanically very stable, can be created by means ofthe webs 21. The branch is suitable for instruments for open surgery aswell as for laparoscopic and flexible endoscopic instruments.

1-15. (canceled)
 16. An electrosurgical instrument comprising a branchhaving a metal part, the metal part comprising: a hinge bore having aplastic jacket that extends through the hinge bore to form a bearingsleeve.
 17. The electrosurgical instrument of claim 16, wherein theplastic jacket is configured to center within the hinge bore a boltinserted into the hinge bore by compensating for production tolerancesin the metal part.
 18. The electrosurgical instrument of claim 17,wherein the plastic jacket insulates the metal part against the bolt.